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This problem trains for: SAT-I, AMC-8, GMAT.

The operator # is the "anti-percent":

5# of a number represents the quantity that is left after removing 5% of the number.

For example:

Which of the statements below models the problem: "If 80% of negative expectations yield negative results and 10% of positive expectations yield positive results, out of a set of 50 negative expectations and 10 positive expectations, how many positive results will there be?"

(problem inspired from "Murphy's Laws")

The number of positive results preceded by negative expectations can be expressed as:

The number of positive results preceded by positive expectations can be expressed as: